VOl. 7s
Dov BEN-ISHAI
4062 [CONTRIBUTION FROM
DEPARTMENT OF ORGANIC CHEMISTRY, LVEIZMASN INSTITUTE
THE
OF
SCIENCE]
The Reactions of 0-Hydroxyethylamides and @-Hydroxyethylcarbamateswith Phosgene BY Dov BEN-ISHAI RECEIVED MAY11, 1956 P-Hydrosyethplamides ( I ) on treatment with phosgene are converted t o p-chloroethylamides (IV). Under similar experimental conditions 8-hydroxyethylcarbamates ( V ) yield only N-carbalkoxy-2-oxazolidones (VII). The reaction mechanism is discussed.
Schroeter and Lewinskil were the first to observe the different response of urethans, as compared with that of amides, to the action of thionyl chloride
+
RCONHz SOClz +R C N 2CzH60CONHz SOClz +HzN-CONHCOOCzHa
+
This observation was later confirmed by Raiford and Freyermuth2who suggested a mechanism to explain the behavior of urethans in this reaction. According to these authors, urethan is first cleaved by thionyl chloride to cyanic acid, ethyl chloride, sulfur dioxide and hydrogen chloride
+ SOCIz +
CzHoOCONHz
HXCO
+ CzHbC1 + SOz + HCI
The cyanic acid formed reacts with a second urethan molecule to give the ethyl allophanate. A similar difference in behavior toward electrophilic reagents is known in the intramolecular cyclizations of amino acid derivatives. Acylamino acid halides rearrange rapidly into the corresponding oxazolone hydrohalidesj3 whereas carbalkoxyamino acid halides afford, under similar conditions, 2,5-0xazolidinediones.~ P-HydroxyalRi-CH-COX
Ri-CH-C=O
I
I
N
iYH
I co I
C~HsOCONHCHzCH~Cl
I n the present paper the reactions of p-hydroxyethylamides and p-hydroxyethylcarbamates with phosgene as an electrophilic reagent are described (Chart I). p-Hydroxyethylamides (I) when treated in dioxane solution with phosgene and then heated on a water-bath afforded the corresponding p-chloroethylamides (IV) in over 80% yield (Table I). Under the same experimental conditions 6-hydroxyethylcarbamates (V) were converted to N-carbalkoxy-2-oxazolidones (VII) in excellent yield (Table 11). The p-chloroethylamides thus obtained were identical (mixed m.p.) with authentic samples prepared from p-chloroethylamine hydrochloride and the corresponding acyl chloride in aqueous alkaline solution. The N-carbalkoxy-2-oxazolidones showed two characteristic carbonyl absorption bands a t 1800 and 1720 cm. -I in the infrared. N-Carbobenzyloxy-2-oxazolidone (VII, R = C7H7) was further degraded to 2-oxazolidone on catalytic hydrogenation and found to be identical (mixed m.p.) with 2-oxazolidone prepared according to Horneyer.’ CHARTI
R Ri-CH-C=O
I
1
‘c/It
I 0 I
I I co I
0
R 0
kylamides resemble acylamino acids and are converted to oxazoliiie hydrochlorides on treatment with thionyl ~ h l o r i d e . ~ RI-CH-CH-R~
I
NH OH
I
co I
R
I
CH~-CH~
”
R
I
c1
RCONHCHzCHzOCOXHz VI11
+ RX
ICH 0 --.)
co
.HX
+ SOClz +
CZH~OCONH-CHZCHZOH
I
R Ri-CH-COX
I h-H I
y
--+
1
0
who found that N - (P-hydroxyethyl)-ethylcarbarnate is converted to N-(p-chloroethy1)-ethylcarbarnate on treatment with thionyl chloride
-
Ri-CH-CH-Rz
SOCL
I
I
N
\c/
0
*HCI
T
CHI-CHz
I
I
OH
co
COClZ
I
R
I
I
I
I
A
+ COZ+
j
co
LR
R
I1
(1) G. Schroeter and M. Lewinski, Ber., 26, 2171 (1893). ( 2 ) L. C. Raiford and H. B. Freyermuth, J. Org. Chem., 8 , 174 ( 1943). (3) H. E. Carter and J. W. Hinman, J. B i d . Chem., 178, 403 (1949). (4) J. S. Fruton, Advances i n Protein Chem., 6, 21 (1949). ( 5 ) R. H. Wiley and L. L. Bennett, Chem. Revs., 44, 447 (1949). (0) H. W’enker, THISJOURNAL, 68, 2608 (1936).
J
111
CHz-CH2
R
The reaction of one p-hydroxyalkylcarbamate with thionyl chloride was reported by Wenker6
1
CHz-YHz
I CHz-CHz
‘ -lr”
NH
IV
A
i I coct
co I
V
I
c1 R
VI
I
0
C ’‘
0 - 0
R
+ ROCO--N
il
0 VI1 ROCOXHCH~CH~OCOXHz IX
(7) A. H. Horneyer, U. S. Patent 2,399,118; C.A., 40, 4084 (19Ui).
Oct. 5 , 1956
P-HYDROXYETHYLAMIDES WITH PHOSGENE
If the reaction mixtures of N-(P-hydroxyethy1)phenylacetamide (I, R = C7H7)or N-(@-hydroxyethyl)-benzylcarbamate (V, R = C7H7) with phosgene were poured into aqueous ammonia solution (instead of being heated on water-bath) they yielded P-phenylacetylaminoethylcarbamate(VII, R = C7H7) or P-carbobenzyloxyaminoethylcarbamate (IX, R = C7H7),respectively. This observation, together with the isolation from N-(P-hydroxyethyl)-p-nitrobenzamide of a crystalline chlorocarbonate which decomposed on heating to yield N-(P-chloroethy1)-p-nitrobenzamide (IV, R = p-02NC6H4),shows the chlorocarbonates I1 and VI to be intermediates in the reaction of both amides and carbamates with phosgene. P-Carbobenzyloxyaminoethylcarbamate (IX, R = C7H;) was further degraded, by the action of hydrogen bromide in glacial acetic acid,8 to Paminoethylcarbamate hydrobromide. The latter compound was converted on phenylacetylation to the P-phenylacetylaminoethylcarbamate,identical with VI11 (R = C7H7). The postulation of oxazolinium chlorides I11 as intermediates in this reaction would best explain the thermal instability of P-acylaminoethyl chlorocarbonate (11) compared with either that of ethyl chlorocarbonate itself or that of @-chloroethyl chlorocarbonate. A neighboring group effect of this type is known in similar casesg Oxazolinium chlorides were not isolated in the reaction discussed, probably since they are not stable under the conditions under which P-acylaminoethyl chlorocarbonates (11) decompose t o yield p-chloroethylamides (IV) . They are obtained from P-hydroxyalkylamides only when treated with thionyl chloride in the cold, whereas P-chloroalkylamides are the only products if refluxing thionyl chloride is used. l o In order to obtain further information as to the mechanisms of the reactions being discussed, the behavior of cis- and trans-d,l-P-benzoylaminocyclohexanol and -P-carbobenzyloxyaminocyclohexanol were examined. The results are summarized in Chart 11. cis- and trans-P-benzoylaminocyclohexanol (X, XIII) on treatment with phosgene afforded crystalline chlorocarbonates XI and XIV, which behaved differently on thermal decomposition. The trans isomer XI was converted to trans-6-benzoylaminocyclohexyl chloride on heating to 140' for five minutes or by refluxing a xylene solution for a short time. The only product isolated after refluxing a xylene solution of the cis-chlorocarbonate XIV was a chlorine-free compound (XV) which showed two carbonyl absorption bands a t 1790 and 1680 cm.-l in the infrared. N-Benzoyl-2-oxazolidone, prepared by benzoylation of 2-oxazolidone, showed exactly the same absorption bands. The cis- and trans-&carbobenzyloxyaminocyclohexanol isomers (XVI, XIX) were converted, after treatment with phosgene and subsequent heating, into the corresponding 2-oxazolidone derivatives XVIII and XX. Both showed the characteristic carbonyl absorption bands of carbalkoxy-2-oxa(8) D. Ben-Ishai and A. Berger, J. Oyg. Cham., 17, 1564 (1952). (9) S. Winstein and R. Boschan, THISJ O U R N A L , 72, 4669 (1950). (10) E.M . Fry, J . Org. Chcm., 14,887 (1949).
4963
CHARTI1
A
NH I
co
co
I
I CeH,
I
0
IXV
I
NH
I
1 0 I
C,H7
I I
0 I C7H7
0
XVII
/
N-C=O
co
XVI
OH
A
co I
i
(ps
+C --O (CI COCI,
NH I CO
co
I CI
XIV
c-4
I 0
1 -
I CH ,,
XI11
XI1
co
co
CH ,,
t to,
C A
XI
co
I
1
I
CeH,
X
NH
NH
co
t HCI
1
C,H,
XVIII
COCI,
I
ll
0
I
CY,
XIX
xx
zolidones (VII) a t 1800 and 1720 cm.-'. The infrared spectra of the two isomers were not identical and a mixed melting point was depressed. Only the trans-chlorocarbonate XVII is stable above 100' and has been obtained as a crystalline compound. These observations support the suggested mechnisms (Chart I). In the case of cis-P-benzoylaminocyclohexyl chlorocarbonate (XIV) oxazolinium chloride formation is sterically not favored and therefore formation of an oxazolidone derivative XV is made possible. The trans isomer XI behaves normally and is converted on heating to trans-0-benzoylaminocyclohexyl chloride (XII). In the case of trans-P-carbobenzyloxyaminocyclohexyl chlorocarbonate (XVII) the steric effect is not strong enough to change the course of the reaction and a trans-oxazolidone (XVIII) has been obtained. Experimentall' Preparation of 6-Hydroxyethy1amides.-N-@-Hydroxyethyl)-benzamide and N-(p-hydroxyethy1)-phenylacetamide were prepared by the general procedure of Phillips and was preBaltzly.12 N-(P-Hydro~yethyl)-p-nitrobenzarnide'~ pared from ethanolamine and p-nitrobenzoyl chloride in 82vo yield by the general procedure of Leffler and Adams.l4 N-@-Hydroxyethyl)-anisamide.-The general procedure of Leffler and Adams14 was used. The product melted a t 105-106" after recrystallization from ethyl acetate; yield 78%. Anal. Calcd. for C:0H13N03: C, 61.5; H, 6.6; N, 7.1. Found: C, 61.6; H, 6.6; N, 7.4. (11) All melting points are uncorrected. (12) A. P. Phillips and R. Baltzly, THISJOURNAL, 69,200 (1947). (13) R.Hill and G. Powell, ibid., 67,1462 (1945). (14) M.T.Leffler and R. Adams, ibid., 69, 2259 (1937).
49 ti4
Dov BEX-ISHAI
Vol. i 8
TABLE I ~-CHLOROETHYLAMIDES, R-CONH-CH2-CHz-C1 Yield,
R
Formula
M.p., o c .
70
CsHs CsHsCH? C,H;OCOSHCH* P-OzXCsHc P-CH30C6H4
CgHi oClr\-0 CloH1zClNO CizHisClNz03 CgHSClS203 CioH12ClNOz
105- 106l o 78-79 115-116 124-125 128- 129
90 90 84 81 91
Chlorine, 5 Calcd. Found
19.4 17.9 13.3 15.5 16.6
19.8 17.4 13.3 15.6 16.5
Nitrogen, yo Calcd. Found
7.6 7.1 10.4 12.3 6.5
7.3 7.2 10.2 12.4 6.4
TABLE I1
R
Formula
CZH5 CJ37 CIH, C6HsCHz P-OzNCsHaCHz
CsHsNO4 CsHiiSOn C7HgNOd CiiHnKOa CiiHioSzOs
N-CARBALKOXY-2-OXAZOLIDOSE (VII) Yield, Carbon, % Calcd. Found 3I.p., o c . %
51-52 53-54 41-42 101-102 171- 173
95 92 90 89 82
N-(0-Hydroxyethy1)-carbobenzyloxyglycineamide.--A solution of 10 g. of ethyl carbobenzyloxyglycinate and 6 g. of ethanolamine in 50 ml. of ethanol was refluxed for one hour and then distilled zn ZJUCUO to dryness. The solid residue was crystallized from ethyl acetate, giving 7 g. (667") of colorless leaflets, m.p. 113-114'. Anal. Calcd. for C12H16N20a: C, 57.1; H , 6.4; K, 11.1. Found: C, 57.3; H, 6.2; N, 10.9. N-(8-Hydroxyethy1)-allylcarbamate.-A mixture of 30.5 g. (0.5 mole) of ethanolamine and 75 g. (0.75 mole) of powdered potassium bicarbonate in 250 ml. of methylene chloride was cooled in an ice-bath and, while stirring, 60.3 g. (0.5 mole) of allyl chlorocarbonate was added over a period of one hour. The potassium salts were filtered off, washed with more methylene chloride and the washings added to the filtrate. The solvent was removed in Z'UCUO and the oily residue distilled. The yield was 62 g. (845),b.p. 122123' (0.8 mm.), n2'D 1.4704. Anal. Calcd. for CGH11N03: C, 49.6; H , 7.6; N, 9.7. Found: C, 49.2; H , 7.4; S,10.0. ~V-((P-Hydroxyethyl)-ethylcarbamate16 and l\r-(p-hydroxyethj 1)-propylcarbamate16 were prepared in 73 and 787, 5 icld as described above for the allyl derivative. N-(p-Hydrouyethy1)-benzylcarbamate was prepared from ethanolamirie and benzyl chlorocarbonate by the method of Rose.17 N-(0-Hydroxyethy1)-p-nitrobenzy1carbamate.-This compound was prepared from ethanolamine and p-nitrobenzyl chlorocarbonate by the general procedure of Leffler and Adams.I4 The product melted a t 102- 103' after recrystallization from ethyl acetate; yield 687,. A n a l . Calcd. for C1OH1?SzOb: C, 50.0; H, 5.0; S , 11.7. Found: C, 50.4; H , 5.3; N, 11.5. Reaction of p-Hydroxyethylamides with Phosgene. General Procedure.-A suspension of 5 g. of the amide in 25 mi. of dry dioxane was saturated with phosgene for halof an hour. During the reaction the temperature rose to 40 aiid the starting material dissolved. The excess phosgene was removed by bubbling dry carbon dioxide through the solution, the dioxane was evaporated under reduced pressure and the residue was heated on the water-bath for another hour. The 0-chloroethylamides thus obtained were crystallized from ethyl acetate-heptane (Table I ) . p-p-Nitrobenzoylaminoethyl Ch1orocarbonate.--iV-(pHydroxyethy1)-p-nitrobenzamide (10 g.) was suspended in 50 ml. of dry dioxane and treated with phosgene as described above (general procedure). The chlorocarbonate melted a t 106-107O dec. after recrystallization from benzene; yield 8 g. (62%). Anal. Calcd. for CloH9ClS20j: C1, 13.0; LT, 10.3. Found: C1, 12.6; h-,10.6. Reaction of p-Hydroxyethylcarbamates with Phosgene .A solution of 5 g. of the carbamate in 25 ml. of dry dioxane was treated with phosgene as described above (general pro( 1 5 ) A. P. M. Francimont and A. Lublin, Rec. ~ Y U V chim., 21, 45 (1902). (16) K. Hess and C1. Uibrig, Ber., 48, 1974 (1915). (17) W. G. Rose, THISJOURNAL, 69, 1384 (1947).
45.3 48.6 49.1 59.7 49.6
45.3 48.5 49.0 59.5 49.8
Hydrogen, So Calcd. Found
5.7 6.4 5.3 5.0 3.8
5.8 6.6 5.4 4.8 3.7
Nitrogen, % Calcd. Found
8.8 8.1 8.2 6.3 10 5
8.5 7.9 8.1 5.9 9.9
cedure) . The ~l~-carbalkox~--2-oxazolidones thus obtained were recrystallized from ethyl acetate-heptane (Table 11)). 0-Phenylacetylaminoethylcarbamate(VIII, R = C7H4 .A-(6-Hydroxyethy1)-phenylacetamide (5 g.) dissolved in 20 ml. of dry dioxane was treated with phosgene as described above (general procedure). After removal of the excess phosgene, the solution was poured into aqueous ammonia containing crushed ice. The white precipitate thus obtained was filtered and crystallized from ethanol-water. The product melted a t 161-162"; yield 3.7 g. (5870). Anal. Calcd. for CllH1&~03: C, 59.5; H , 6.4; X, 12.6. Found: C, 59.4; H , 6.4; N, 12.4. p-Carbobenzyloxyaminoethylcarbamate( I S , R = C7H7). -The procedure just described was repeated using 10 g. of S-(P-hydroxyethy1)-benzylcarbamate dissolved in 30 ml. of dioxane. The product melted a t 115-116' after recrystallization from ethanol-n-ater; yield 11 g. (92%). Anal. Calcd. for Cl1HlaK2O4: C, 55.5; H , 5.9; K, 11.7; Found: C, 55.8; H , 5.7; N, 11.4. 8-Aminoethylcarbamate Hydrobromide .--8-Carbobenzyloxyaminoethylcarbamate was treated with hydrogen bromide in glacial acetic acid.* The hydrobromide melted a t 147-148' after recrystallization from alcohol-ether; yield
84%. Anal. Calcd. for C3H9BrS:02: Br, 43.1; S, 15.1. Found: Br, 42.7; K, 14.8. 2-Oxazolidone.-S-Carbobenzyloxy-2-oxazolidone (2 8.) was suspended i n 60 ml. of alcohol and catalytically hydrogenated under 4 atm. pressure and in the presence of 10% palladized charcoal (0.2 g . ) . After three hours, the solution was filtered from the catalyst and evaoorated in Z Q C U O to dryness. The product melted a t 89" after recrystallization from benzene and this 1n.p. was not depressed on admixture with an authentic samule of 2-oxazolidone.' The yield was 0.68 g. (86%). Preparation of 2-Aminocvclohexanol Derivatives. d,lt i ans-%Benzoylaminocycloh6xanol X .-The procedure of The product McCasland, Clark and Carter was melted a t 174-175' after recrystallization from eth>-l acctate. d,Z-cis-2-AminocyclohexanolHydrochloride.--d,l-lrans-2Benzoylaminocyclohexanol (X) mas converted to d,Z-cis-2aminocyclohexanol by the method of Johnson and Schubert .I9 d,Z-cis-2-Benzoylaminocyclohexanol(XIII) .-The procedure of McCasland, Clark and Carter nasused.'* The product melted a t 188-189' after recrystallization from ethyl acetate. d,Z-trans-2-Carbobenzyloxyaminocyclohexanol(XVI) .This compound was prepared from d,Z-trans-2-amitiocyclohexanol and benzyl chlorocarbonate by the Schotten; Baumann procedure. The product melted a t 101-102 after recrystallization from heptane; yield 8470. Anal. Calcd. for C14HdJ03: C, 67.4; H , 7.6; N, 5.6. Found: C, 67.2; H , 7.4; N , 5.7. (18) G . E . XIcCasland, R.K . Clark and F I . 1;. Carter, i b i d . , 71, 637 (1949).
(19) W. S. Johnson and E . S . Schubert, i b i J . , 72, 2187 (1950).
Oct. 5 , 1956
ISOTHIOCYANIC ACIDAND OLEFINICCOMPOUNDS
d,Z-cis-2-Carbobenzyloxyaminocyclohexanol (XIX) .d,Z-cis-2-Aminocyclohexanol was carbobenzoxylated as described above for the trans isomer. The product melted a t 72-73' after recrystallization .from heptane; yield 88yo. Anal. Calcd. for C1aH1gh703: C, 67.4: H, 7.6; Pi, 5.6. Found: C, 67.4; H, 7.3; N,5.5. d,Z-trens-2-BenzoylaminocyclohexylChlorocarbonate (XI) . -One gram of the benzamido alcohol X was suspended in 15 ml. of dry dioxane and treated with phosgene as described above (general procedure). After removal of the solvent the residue was recrystallized from benzene-petroleum ether and melted a t 134" dec. The yield was 1.1 g. (90%). Anal. Calcd. for C14HlsC1N03: C1, 12.6; N, 5.0. Found: C1, 12.7; K, 5.3. d,I-trans-2-BenzoylarninocyclohexylChloride (XII) .-This compound was obtained in 6470 yield by heating the chlorocarbonate X I to 140" for 5 minutes in an oil-bath. The product melted a t 165-166" after recrystallization from benzene and this m.p. was not depressed on admixture with a sample prepared according to Johnson and Schubert.Ig d,Z-cis-Benzoylaminocyclohexyl Chlorocarbonate (XIV).The procedure described above for the preparation of th: trans isomer was used. The product melted a t 112-113 dec. after recrystallization from benzene-petroleum ether; yield 88%. A n d . Calcd. for C14HIGClN03: C1, 12.6; N, 5.0. Found: C1, 12.9; N, 5.3. N-Benzoyl-d,Z-cis-4,5-cyclohexano-2-oxazolidone (XV) .-
This compound was obtained by refluxing a xylene solution of the chlorocarbonate XIV for 3 hours and distillation in uacuo to dryness. The product melted a t 114-115'' after recrystallization from hexane; yield 74%. Anal. Calcd. for C14H15NO3: C, 68.6; H , 6.1; N, 5.7. Found: C,68.8; H , 5.8; N,5.8.
[CONTRIBUTIONFROM
t-Carbinamines, RR'R"CNH2.
THE
4965
N-Benzoyl-2-oxazolidone.-2-Oxazolidone was benzoylated by the procedure of C1ose.m The product melted a t 171-172" after recrystallization from ethyl acetate-hexane; yield 54%. Anal. Calcd. for C10HION03:N, 7.3. Found: N, 7.1. d,l-truns-2-CarbobenzyloxyaminocyclohexylChlorocarbonate (XVII) .-One gram of the carbobenzyloxaminoalcohol XVI was dissolved in 10 ml. of dry dioxane and treated with phosgene as described above. The chlorocarbonate melted a t 112-113" dec. after recrystallization from heptane; yield 1.05 g. (85%). Anal. Calcd. for ClsHI8C1NO4: C1, 11.4; N, 4.5. Found: C1, 11.6; N, 4.6. N-Carbobenzyloxy-d ,l-tr~ns~,5-cyclohexano-2-oxazolidone (XVIII) .-This compound was obtained by refluxing a xylene solution of the chlorocarbonate XVII for one hour and distillation in vacuo to dryness. The product melted a t 88-89' after recrystallization from ethyl acetate-hexane: yield 80%. Anal. Calcd. for CISH1,NO4: C, 65.5; H , 6.2; N, 5.1. Found: C, 65.9; H , 6.2; N, 5.2. N-Carbobenzyloxy-d ,Z-~is~,5-~yclohexano-2-oxazolidone (Xx).-One gram of the carbobenzyloxyaminoalcohol XIX was dissolved in 10 ml. of dioxane and treated with phosgene as described above. The oily residue left after evaporation of the solvent was heated for 2 hours on a waterbath. The product melted at 92-93' after recrystallization from heptane; yield 0.9 g. (82%). Anal. Calcd. for ClSH1,N04: C, 65.5; H, 6.2; N, 5.1. Found: C, 65.9; H , 6.4; N,5.4. (20) W. J. Close, THIS JOURNAL, 73, 95 (1951).
REHOVOTH, ISRAEL
ROHM& HAASCOMPANY]
IV. The Addition of Isothiocyanic Acid to Olefinic Compounds1
BY LEOS. LUSKIN,G. E. GANTERT AND W E CRAIG RECEIVED APRIL12, 1956 Isothiocyanates were obtained by addition of isothiocyanic acid to diisobutylene, styrene and a-methylstyrene. addition to acrylic esters gave 3-thiocyanatopropionates.
The addition of isothiocyanic acid to unsaturated hydrocarbons2 and a,p-unsaturated ketones3 has been reported t o give thiocyanates or isothiocyanates. However, the identification of the products often has been confusing. The possibility of the formation of mixtures also has been recognized, but these have been carefully examined only in the products obtained from isobutylene.2c The addition of isothiocyanic acid to several olefins has now been studied. The structure of the resulting products was determined by physical examination and by comparison with the compounds obtained by alternative methods. In the addition reactions, nascent isothiocyanic acid was generated by the addition of aqueous sul(1) Presented a t the Delaware Valley Regional Meeting of the American Chemical Society, Phlladelphia, Penna., February 16, 195G. (2) (a) F. Challenger, A. L. Smith and F. J. Patton, J. Chem. Soc., 123, 1046 (1923); (b) W. Lee, U. S. Patent 1,992,533; (c) M. S. Kharasch, E. M. May and F. R . ,Mayo, THIS JOURNAL, 69, 1580 (1937); E . M . May, Ph.D. Thesis, University of Chicago, 1938; (d) H. Bruson and T . W. Rieuer, U. S. Patent 2,393,746; ( e ) H. Bruson, U. S. Patents 2,395,464, 2,395,456 and 2,411,869; ( f ) R. P. Naylor, J . C h e m . SOL.,247 (1945). (3) IT. Bruson, U. S. Patent 3,395,453; R. A. Mathes, F. D. Stewart and F.Swedish, Jr., THISJ O U R N A L , 70, 1452 (1948).
Similar
furic acid to sodium thiocyanate slurried with the olefin. Successful additions were achieved with typical branched aliphatic and aromatic olefins and with acrylic esters (Table I). Attempts to extend the reaction to acrylonitrile and to methacrylates failed. Infrared spectrophotometry was used to distinguish possible thiocyanates which have a strong, very sharp peak a t 2130-2160 c1n-I while isothiocyanates show a broad, very strong band a t 2040 to 2180 c ~ . - I . ~ When measured in dilute (4) W. Gordy and D. Williams, J . Chem. Phys., 3, 664 (1935); 41 85 (1936); F. Pristera, AfiPI. Specfuoscogy, 6, No. 3, 29 (19.52); E . C. Taylor, Jr., J. Wolinsky and H. Lee, THISJOURNAL, 76, 1866 (1954); National Research Council-National Bureau of Standards Compound Cards No. 481 to 483; Sadtler Infrared Spectra No. 3104 to 3115, 5753, etc. In our work, ethyl thiocyanate was used as a standard, peak a t 2160 em.-'. ( 5 ) W. Gordy and D. Williams, J. Chem. Phys., 4 , 85 (1936); D . Williams, i b i d . , 8, 513 (1940); J . Carol and L. L. Ramsey, J . A x o c . O f i c . Agu. Chcmisfs, 36, 967 (1953); R. A. Ludwig, G. D. Thorn and C. H. Unwin, Con. J . Botany, 33, 42 (1955); M. G. Ettlinger and J . E. Hodgkins, THIS J O U R N A L , 77, 1831 (19.55); M. G. Ettlinger and A. J . Lundeen, ibid., 78, 1952 (1956). In this work, l-butyl isothiocyanateQb was used as a standard, peaks a t 2090 and 2000 ern.-'. A similar shift in location has been observed for nitriles and isonitriles; J. J. McBride and H. C. Beachell, THIS JOURNAL, 7 4 , 5247 (1952); D. Samuel, B. Weintraub and D. Ginsburg, J . Oug. Chcm., 21, 376 (1956).
